The present invention generally relates to compression molding and, more particularly, is concerned with an apparatus and method for producing a compression molded product.
In a compression molding process, a body of material is typically placed directly in a cavity of the mold of a die set and compression molding takes place under application of pressure with the plug of the die set. Many fiber-reinforced composite structures are formed using this process. In order to obtain good bonding between the reinforcing fibers and polymer matrix of a composite material as well as to protect the fibers during subsequent molding, the reinforcing fibers are surface treated by impregnation to enhance adhesion to the polymer matrix. The resulting partially cured material is commonly called a prepreg.
Pressure is applied to the mold and/or plug of the die set to accomplish the compression into the desired form of the prepreg lay-up in the mold. Pressure can be applied by a vacuum-bagging technique wherein the pressure required to form the shape and create good bonding is obtained by covering the lay-up prepreg with a plastic bag and then creating a vacuum in the mold cavity. Heat is also applied to fully cure the material. If additional heat and pressure are desired, the entire die set and prepreg are placed in an autoclave.
A problem of the above-described conventional compression molding process is the high cost and complexity associated with the conventional application of heat and pressure to the process. Consequently, a need still exists for an innovation which will provide a solution to the aforementioned problem.